Crossover - When Christian GF helps you relax you after all the demon cleansing:

I've always found the concept of Joan of Arc mildly humorous.

Just you're king and everything, there's a couple of guys that don't like you but they're mostly handled and then one day some teenage girl shows up in armor says "God says you're fired." and your enemies all through the power of now having a waifu mascot overthrow you.

I know it's an incredibly over-simplified account of the events but it's what I remember generally happening.

Christian GF would be slaughtering demons right alongside the Slayer.